Cell Division & Reproduction

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Transcript Cell Division & Reproduction

10.1-Cell Growth, Division, & Reproduction
Limits to Cell Size
The larger a cell becomes, the more demands
the cell places on its DNA. In addition, a
larger cell is less efficient in moving nutrients
and waste materials across its cell membrane.
Information Overload
Living cells store critical information in DNA.
As a cell grows, that information is used to build
the molecules needed for cell growth.
As size increases, the demands on that
information grow as well. If a cell were to grow
without limit, an “information crisis” would occur.
Exchanging Materials
Food, oxygen, and water enter a cell through the cell
membrane. Waste products leave in the same way.
The rate at which this exchange takes place depends
on the surface area of a cell. The rate at which food
and oxygen are used up and waste products are
produced depends on the cell's volume.
The ratio of surface area to volume is key to
understanding why cells must divide as they grow.
Division of the Cell
Before a cell grows too large, it divides into two new
“daughter” cells in a process called cell division.
Before cell division, the cell copies all of its DNA
It then divides into two “daughter” cells. Each
daughter cell receives a complete set of DNA.
Cell division reduces cell volume. It also results in an
increased ratio of surface area to volume, for each
daughter cell.
Cell Division & Reproduction
The production of genetically identical
offspring from a single parent is known as
asexual reproduction
Offspring produced by sexual reproduction
inherit some of their genetic information
from each parent
Asexual Reproduction
In multicellular organisms, cell division leads to growth.
It also enables an organism to repair and maintain its
body.
In single-celled organisms, cell division is a form of
reproduction.
Asexual reproduction is reproduction that involves a
single parent producing an offspring. The offspring
produced are, in most cases, genetically identical to the
single cell that produced them.
Asexual reproduction is a simple, efficient, and
effective way for an organism to produce a
large number of offspring
Both prokaryotic and eukaryotic single-celled
organisms and many multicellular organisms can
reproduce asexually
Sexual Reproduction
In sexual reproduction, offspring are produced
by the fusion of two sex cells—one from each of
two parents. These fuse into a single cell before
the offspring can grow.
The offspring produced inherit some genetic
information from both parents.
Most animals and plants, and many single-celled
organisms, reproduce sexually.